Apparatus for closing open-topped flexible containers

ABSTRACT

In an apparatus for closing open-topped containers made of flexible material, such as sausage casings, displacement of a single drive element serves to flatten the mouth of the container and then to compress it transversely, surround it with a U-shaped clip and close the clip to seal the container. The drive element is a punch which carries a cam whose advancing contour causes a pair of gathering arms surrounding the top of said container to pivot about pins against the action of springs and thereby flatten the container top. Further advance of the punch carries the clip and ultimately closes it. Braking means such as a piston-cylinder or springs may be provided to slow down the advance of the punch during a part of the stroke as compared to the final part of the stroke when the full velocity is desired to close the clip.

United States Patent n 1 Niedecker [5 APPARATUS FOR CLOSING OPEN- TOPPEDFLEXIBLE CONTAINERS [76] Inventor: Herbert Niedecker, Am Ellerhang 6,

6243 Falkonstein (Taunus), Germany 7 [22] Filed: Feb. 22, 1971 [21]App]. No.1 117,570

[30] Foreign Application Priority Data Feb. 28, 1970 Germany ..P 2009541.4 Sept. 12, 1970 Germany ..P 20 45 229.3

[52] US. Cl. ..53/138 A, 29/243.57 [51] Int. Cl. ..B65b 51/04 [58] Fieldof Search ..29/2ll D, 243.56, 243.57; 53/138 A [56] References CitedUNITED STATES PATENTS 2,733,442 2/1956 Russell et al. ..29/243.573,381,359 5/1968 Schroeder ,.29/243.57 X

[451 Feb. 27, 1973 Primary Examiner--Robert C. Riordon AssistantExaminer-Neil Abrams Attorney-Dinklage & Sprung [57] ABSTRACT ln anapparatus for closing open-topped containers made of flexible material,such as sausage casings, displacement of a single drive element servesto flatten the mouth of the container and then to compress ittransversely, surround it with a U-shaped clip and close the clip toseal the container. The drive element is a punch which carries a camwhose advancing contour causes a pair of gathering arms surrounding thetop of said container to pivot about pins against the action of springsand thereby flatten the container top. Further advance of the punchcarries the clip and ultimately closes it.

Braking means such as a piston-cylinder or springs may be provided toslow down; the advance of the punch during a part of the stroke ascompared to the final part of the stroke when the full velocity isdesired to closethe clip.

11 Claims, 6 Drawing Figures PATi-jmmnzaznm sum 1 or 4 Inventor:HERBERTNIEDECKER BY BURGESS, DINKLAGE & SPRUNG TORNEYS.

PATENTEDFEBZYIQYK 3, 71-7, 972

SHEET? [1F 4 in van tor BYHERBERT NIEDECKER BURGESS, DINKLAGE 8- SPRUNGAT TORNE YS.

. PATENTED Z 7 73 SHEET 3 OF 4 j 4 HY m 5 F F all BURGESS, DINKLAGE asfiune ATTORNEYS APPARATUS FOR CLOSING OPEN-TOPPED FLEXIBLE CONTAINERSThe invention relates to an apparatus for closing packages of a flexiblematerial, such as plastic film, "used for packaging food products andother articles e.g., sausage casings. I p

Such machines are frequently required in sausage factories, for example,for the rapid and dependable closing of sausage casings, particularlysausages of relatively large diameter, immediately after being filled.In operation, the top of the package is displaced by gathering it towardthe axis of the package, followed by sealing the top with a U-shapedclip whose legs are displaced and closed by a punch and die.

Machines which perform these operations are known.- They usually consistof a pneumatically actuated punch and a die for closing the closureclip. One such machine, shown in U.S. Pat. No. 3,293,736, is providedwith two gathering arms which are supported on a common pin and aredriven by two separate, additional compressed-air cylinders.

In another machine for this purpose, shown in U.S. Pat. No. 3,377,692,twoprism-shaped gathering plates are provided which are carried inguides and which work against each other in gathering. A compressed-aircylinder with a piston is provided for actuation of the gatheringplates, and another compressed-air cylinder for. driving the punch.FromU.S. Pat. No. 2,756,428 it is known to close two closing armsthrough a lever linkage from a common drive so as to close a clip.

These prior-art devices are rather complicated technically and, sincethey comprise a plurality of drives, they are susceptible to trouble inseveral respects.

It is accordingly an object of the invention to provide a sealingapparatus of the general type described wherein a single drive mechanismeffects both gathering of the container top and its closure.

It is afurther object to provide such an apparatus wherein the rate ofadvance of the drive mechanismis controlled so as to be at differentlevels at different portions of th'e'stroke or cycle, the particularlevel being coordinated to the function being performed.

These and other objects and advantages are realized in accordance withthe present invention wherein a single drive-element is provided on anapparatus suited for sealing sausage casings with U-shaped clips. Theapparatus comprises a base provided with a longitudinal guide channeland a punch movable longitudinally of said guide channel. The U-shapedclips are successively movable, from a supply, in said guide channel. Apair of gathering arms are pivotally connected to said base on thecontainer. A punch is caused to advance and, by the interaction of acam-and-follower, one connected to said punch and the other to saidgathering arms, the gathering arms are pivoted so as to flatten the topof the container. Further advance of the punch carries the .clo'sureclip transversely of the flattenedtop, comspout. Generally a length oftubing which has first been closed at one end will be slipped onto thefilling spout,

then the apparatus in accordance with the invention will be moved toalign its closure axis with that of the filling spout and, afterfilling, the open end of the filled container will be gathered andclosed by means of the apparatus in accordance with the invention.

The apparatus in accordance with the invention has the advantage thatbut a single drive element, usually a drive piston, is required for thegathering and sealing operation. During the down stroke of the punchdrive, the two gathering arms are automatically brought togetherconcentrically around the packaging tube, and

I the continued advance of the punch causes the closure .opposite sidesof the channel, surrounding the top of a clip on the die to be appliedaround the gathered top. The requisite synchronization of the gatheringand closing operations and axial sealing are thus assured. Moreover, theapparatus is much. simpler than the prior-art closing machines in whichtwo separate drives are provided for each gathering arm plus anotherseparate drive for the punch. Because of its simpler design, theapparatus in accordance with the invention is reliable and trouble-freein operation. i

A special embodiment of the invention relates to a further improvement.When the packaging tube is first gathered laterally into a flattened topby gathering arms which are closed by the punch drive, and then gatheredinto a round top by the clip advanced by the punch, a rise in pressurewill be produced behind the piston of the pneumatically actuated punchdrive due to the resistanceto be overcome in the first gatheringoperation, i.e., flattening. Upon completion of that gatheringoperation, the increased pressure will have a deleterious effect in thelast gathering operation, i.e., forma-' tion of a circular bundle, inthat thestroke velocity of the punch will be excessive, as a result ofwhichthe wrapper may well be damaged and packaged product, such assausage meat, may be squeezed out. This disadvantage could not beadequately remedied by reducing the speed of the punch drive, in amanner which in itself is known, as this would have the drawback ofslowing down the entire operation, with the machine-then workinguneconomically.

The invention therefore provides for connecting the punch drive with abrake mechanism that reduces the stroke velocity of the punch over acertain section of its path to the die. This is accomplished by causingthe punch to move at full speed over the first portion of its path tothe die; then the punch motion is decelerated over a certain portion ofthe stroke, with the clip carried by the punch at the sametime'performing the In a preferred embodiment, the brake mechanism inaccordance with the invention consists of a brake piston which isconnected to the punch drive piston, and to the punch itself, thebrakingpath being determined by the length of a cylindersurface which'cooperates with the brake piston. In addition, the braking force may beadjusted by means of a pressure-regulating valve. The stroke-limitingmeans for the punch drive, which is advisable in the case ofair-powdered closing machines and through which the desired closingpressure is set, may be fixed to a piston rod coaxial with andpreferably integral with the drive piston and the brake piston. Thecylinder for the brake piston then also serves as a protective sleevefor the stroke-limiting means.

In another embodiment of the invention, the brake mechanism consists ofone or more springs whose force opposes the stroke velocity over thedesired brake path in conjunction with an appropriately constructed partof the punch drive.

The design in accordance with the invention of airpowered closingmachines has the advantage that it precludes damage to the packagingmaterial as it is gathered by the closure clip prior to being closed.The

' closing machine thus is more reliable and trouble-free in operation.

The invention will now be described in greater detail with reference tothe accompanying drawings, wherein:

FIG. 1 is a top plan view of one apparatus embodiment in open position;

FIG. 2 is a bottom plan view of the apparatus of FIG.

1 in closed position;

FIG. 3 is a fragmentary view of another apparatus embodiment with camparts on the gathering arms;

FIG. 4 is a fragmentary view of still another embodiment with a cam foropening the gathering arms;

FIG. 5 shows another embodiment with a spring brake in the startingposition; and

FIG. 6 shows the apparatus of FIG. 5 at the comniencement of the brakingaction.

Referring now more particularly to the drawings, in FIGS. 1 and '2 thereis shown an air-powered closing machine having a base 1 with a punch 2which is rigidly fixed to the piston rod 3 of a drive piston 4. Duringits stroke, the punch 2 drives a U-shaped clip 5 through a clip guidechannel 6, defined in base 1, against a closing die 7.

Before the clip 5 is closed, the packaging material 8 must be gatheredso that it can be closed by the clip 5. Gathering is accomplished bymeans of gathering arms 9 and 10 which are pivotally carried onrespective pins 11 and 12 and held in the open starting position byextension springs 13 and 14. Mounted fixedly or adjustable on rearwardextensions 16 and 17 of the gathering arms 9 and 10 are cam rollerfollowers 18 and 19. In the starting position of the gathering arms, thecam roller followers 18 and 19 are located at point 20 of the cam 15,thus limiting the open position. The gathering arms are closed by meansof the cam 15, which is fixed to the piston rod 3 and the closing punch2, and in the process laterally constrict the packaging material sofiguration and closes it against the die 7.

After the closing of the gathering arms 9 and 10, there occurs behindthe closing piston 4 a pressure rise which would increase the strokevelocity of the punch 2, as a result of which the packaging tube wouldbe damaged by the force of clip 5 against the die 7. To prevent this,there is secured to the piston rod 3 a further brake piston 23 whichupon completion of the initial gathering operation comes to bear, by itscollar 24, on the rim 25 of a brake cylinder 26 (FIG. 2). When thepackaging tube has been laterally gathered to a flattened top with themachine in this position, the rollers 18 and 19 of the gathering arms 9and 10 leave the inclined faces of the cam 15 to ride along the parallelfaces of the cam 15 with less resistance. As a result, the brakingaction of the brake piston 23 becomes effective at this point. Afterleaving the surface of the brake cylinder 26, the braking action ceases.The full force of the closing piston 4 then is available for the closingprocess.

The brake cylinder 26 is sealed with a gasket 27, and the air undergoingcompression can therefore escape only through pressure-regulating valve28, which also serves to regulate the braking force. A check valve 29 isprovided to prevent compression from occurring during the return motionof the punch 2 and of the piston rod 3, and to enable the brake piston23 to return rapidly to its starting position, actuated by the restoringforce of a spring 30.

At its upper end, the piston rod 3 is provided with a screw thread ontowhich a stroke-limiting nut 31 is screwed. This permits the desiredclosing pressure to be set. For reasons of safety, the extended pistonrod with the stroke-limiting nut 31 is provided with a protectivesleeve. The latter is formed by the brake cylinder 26. To permit readyaccess to the stroke-limiting nut 31, a cap 33 provided with a hinge 32is disposed on the protective sleeve. The hinge can be positioned sothat the cap 33 automatically closes, the cylinder 26 with the brakepiston 23 and the stroke-limiting nut 31 then being protected at alltimes against dirt.

The gathering arms 9 and 10 with the clip guide surfaces 21 and 22 andthe die 7 are prevented from striking metallically hard against eachother during the rapid closing motion by means of elastic stops 34 and35 on base 1 which are struck by check arms 36 and 37, carried asrearward extensions of the gathering arms 9 and 10. During the return,the cam 15 gradually releases the roller followers 18 and 19, so thatthe gathering arms 9 and 10 can likewise be pulled into their startingposition, shown in FIG. j1, by the extension springs '13 and 14. Theclosing apparatus is connected to the filling machine through a holdingdevice, not shown, so as to be displaceable with it or rotatable about abore 38.

In the embodiment shown in FIG. 3, the cam 15 is replaced by another cammechanism. Two rollers 39 are rotatably carried on a pin 40 which isfixed to the punch 2 and the piston 4. The rearward extensions 16 and 17of the gathering arms here are provided with cam surfaces 41 and 42which cooperate with the rollers 39. FIG. 3 is a fragmentary view of thegathering arms in the open position. The closed position of thegathering arm 10 is indicated in phantom lines. The gathering operationis completed with the cam surface 41 in position 43 and is followed bythe closing operation. At 44 the roller 39 is in the closing position.

A further example of a cam mechanism is shown in FIG. 4. Here the opencam is replaced by a closed cam track 45, and the two extension springs13 and 14 may therefore be dispensed with. The two pins 11 and 12 aredisposed on a bridge 46 in order that the downward movement of the cam45 may not-be impeded by the pins.

FIGS. 5 and 6 show another embodiment wherein the punch drive with thecam 15 is braked directly by spring force over a certain portion of thestroke. A cam 47 is secured, in conjunction with the cam 15, to thepiston rod 3 of the drive piston 4. On cam 47 ride rollers 48 and 49,which are subject to the adjustable tension of a spring 50, and which,by reason of the inclined surfaces 51 and 52, produce a braking actionduring gathering by the closure clip. Upon completion of the gatheringprocess rollers 48, 49 reach the parallel sides of cam 47 so that thebraking action is discontinued and the full force of the drive piston isavailable for closing the clip.

As noted, the stroke can be initiated manually, return being achieved byspring action. Preferably, however, the stroke is carried outpneumatically, compressed air being supplied above piston 4 through theaperture above it and to the right in FIGS. 1 and 2. Means, not shown,are provided to allow venting of such compressed air during the returnstroke.

It will be appreciated that the instant specification andexamples'areset forth by way of illustration and not limitation, and that variousmodifications and changes may be made without departing from the spiritand scope of the present invention.

What is claimed is:

1. An apparatus for closing open-topped containers of flexible materialsuch as-sausage casings, said ap paratus comprising a base provided witha longitudinal guide channel, a punch movable longitudinally of saidguide channel, a plurality of U-shaped closure clips successively movedin said guide channel from an initial position to a final closedposition sealing a container, a pair of gathering arms pivotallyconnected to said base on opposite sides of said guide channel andsurrounding and spaced from the top of said opentopped container, a pairof pins on said base each serving as the pivot axis of one of saidgathering arms, means for closing said gathering arms, and means foradvancing said punch and one of said clips to final position after saidgathering arms have been closed, said means for closing said gatheringarms comprising camand-follower means mounted on said means foradvancing said punch and on said gathering arms, whereby during advanceof said punch said cam-andfollower means first produces pivoting of saidarms toward one another to form a flattened area embracing thenow-flattened container top, further advance of said punch carrying .aclip in the guide channel transversely of the flattened top to compressthe top to an approximate circle and finally to seal it' by displacingthe legs of the U-shaped clip, gathering of said container top and itsfurther compression and sealing being thereby effected by a singlemechanism in a single continuous stroke.

2. An apparatus according to claim 1, wherein said cam-and-followermeans comprises symmetrical cam and follower means, said cam means beingam one of (a) said means for advancing said punch an (b) sald gatheringarms, and said follower means being on the other of (a) and (b), saidapparatus further including spring means extending between said base andsaid gathering arms, whereby advance of said punch through theintermediary of said cam means and follower means causes said gatheringarms to pivot about their pins against the action of said. spring means.

3. An apparatus according to claim 3, wherein said cam means is on saidmeans for advancing said punch, and said follower means comprises a pairof followers each on one of said gathering arms.

4. An apparatus according to claim 3, wherein said follower means is onsaid means for advancing said punch, and said cam means comprises a pairof guide surfaces each on one of said gathering arms.

5. An apparatus according to claim 1, including brake means carried bysaid means for advancing said punch, whereby the forward velocity ofsaid punch is reduced during a predetermined portion of its advance.

6. An apparatus according to claim 6, wherein said brake means ispositioned so as to reduce the forward velocity of the punch during aportion of the stroke to a level below its final velocity duringdisplacement of the I legs of said U-shaped clip.

7. An apparatus according to claim 6, wherein said brake means comprisesa piston connected with said 8. An apparatus according to claim 8,including an adjustable member on said piston and a stop in fixedposition relative to said base, abutment between said member and saidstop determining the end of a stroke.

9. An apparatus according to claim 6, wherein said punch carries the camof said cam-and-follower means, and said brake means comprises a springwhich is distended upon displacement of said cam, the shape of said camcontrolling the extent of braking.

10. An apparatus according to claim 4, including a piston connected withsaid means for advancing said punch,

a cylinder in which said piston operates, whereby the forward velocityof said punch is reduced during a predetermined portion of its advance,an adjustable member on said piston, and a stop in fixed positionrelative to said base, abutment between said member and said stopdetermining the end of a stroke.

11. An apparatus according to claim 1 in combination with an open-toppedsausage casing disposed between saidgathering arms and means for fillingsaid sausage casing while so positioned

1. An apparatus for closing open-topped containers of flexible materialsuch as sausage casings, said apparatus comprising a base provided witha longitudinal guide channel, a punch movable longitudinally of saidguide channel, a plurality of U-shaped closure clips successively movedin said guide channel from an initial position to a final closedposition sealing a container, a pair of gathering arms pivotallyconnected to said base on opposite sides of said guide channel andsurrounding and spaced from the top of said open-topped container, apair of pins on said base each serving as the pivot axis of one of saidgathering arms, means for closing said gathering arms, and means foradvancing said punch and one of said clips to final position after saidgathering arms have been closed, said means for closing said gatheringarms comprising cam-and-follower means mounted on said means foradvancing said punch and on said gathering arms, whereby during advanceof said punch said camand-follower means first produces pivoting of saidarms toward one another to form a flattened area embracing thenow-flattened container top, further advance of said punch carrying aclip in the guide channel transversely of the flattened top to compressthe top to an approximate circle and finally to seal it by displacingthe legs of the U-shaped clip, gathering of said container top and itsfurther compression and sealing being thereby effected by a singlemechanism in a single continuous stroke.
 2. An apparatus according toclaim 1, wherein said cam-and-follower means comprises symmetrical camand follower means, said cam means being on one of (a) said means foradvancing said punch and (b) said gathering arms, and said followermeans being on the other of (a) and (b), said apparatus furtherincluding spring means extending between said base and said gatheringarms, whereby advance of said punch through the intermediary of said cammeans and follower means causes said gathering arms to pivot about theirpins against the action of said spring means.
 3. An apparatus accordingto claim 3, wherein said cam means is on said means for advancing saidpunch, and said follower means comprises a pair of followers each on oneof said gathering arms.
 4. An apparatus according to claim 3, whereinsaid follower means is on said means for advancing said punch, and saidcam means comprises a pair of guide surfaces each on one of saidgathering arms.
 5. An apparatus according to claim 1, including brakemeans carried by said means for advancing said punch, whereby theforward velocity of said punch is reduced during a predetermined portionof its advance.
 6. An apparatus according to claim 6, wherein said brakemeans is positioned so as to reduce the forward velocity of the punchduring a portion of the stroke to a level below its final velocityduring displacement of the legs of said U-shaped clip.
 7. An apparatusaccording to claim 6, wherein said brake means comprises a pistonconnected with said means for advancing said punch, and a cylinder inwhich said piston operates.
 8. An apparatus according to claim 8,including an adjustable member on said piston and a stop in fixedposition relative to said base, abutment between said member and saidstop determining the end of a stroke.
 9. An apparatus according to claim6, wherein said punch carries the cam of said Cam-and-follower means,and said brake means comprises a spring which is distended upondisplacement of said cam, the shape of said cam controlling the extentof braking.
 10. An apparatus according to claim 4, including a pistonconnected with said means for advancing said punch, a cylinder in whichsaid piston operates, whereby the forward velocity of said punch isreduced during a predetermined portion of its advance, an adjustablemember on said piston, and a stop in fixed position relative to saidbase, abutment between said member and said stop determining the end ofa stroke.
 11. An apparatus according to claim 1 in combination with anopen-topped sausage casing disposed between said gathering arms andmeans for filling said sausage casing while so positioned.